Idler gear refers to a gear that plays a transmission role between two non-contact transmission gears, while meshing with these two gears to change the direction of rotation of the passive gear and make it the same as the driving gear. Its function is only to change the steering and cannot change the transmission ratio, and it is called an idler gear. The idler gear is the intermediate gear, which changes the direction of rotation of the final output shaft. In manual car transmissions, the idler gear definitely refers to the reverse intermediate gear. Only by adding an idler gear can reverse gear be achieved.
The main functions of the idler wheel include changing the steering of the driven wheel, increasing the transmission distance, and adjusting the pressure angle. The idler gear is a transitional part of the gear train that does not change the transmission relationship, in order to make the force on the gear train more reasonable or meet the layout of the entire transmission system. Its function is only to change the steering, not the transmission ratio. The wheelbase can be extended through the idler gear. The number of teeth has no effect on the transmission ratio value, but it will have an impact on the steering of the final wheel. It is a wheel that does not work and has a certain energy storage function, which is helpful for system stability.